Wiper arm testing device or the like



Dec. 24, 1963 F. R. scHRoEDER 3,115,035

wIPER ARM TESTING DEVICE 0R THE LIKE Filed May 31. 19Go 73 my 4 15 .13INVENTOR.

76 FREDERIC/1 SCHROE'DE'Z? BY @um Mwwm. F19 8 ATTORNEYS United StatesPatent ilice The present invention relates generally to the iield 0fscales and more particularly to an improved tester for measuring thetension of the spring in a windshield wiper arm. While the followingdescription will refer exclusively to the testing of the pressure of awiper arm, it will be appreciated that the disclosed scale possessesnumerous features applicable tothe general scale art.

lt is one object of the present invention to provide an improvedwindshield wiper arm pressure tester in which the platform on which theend of the wiper arm is placed during testing moves a very smalldistance thereby permitting the spring in the wiper arm to be tested inthe attitude which it normally assumes during wiper operation, tothereby provide the person testing the arm with an accurate reading ofthe pressure provided by the arm in operation.

Another object of the present invention is to provide an improved wiperarm pressure tester which consists of a relatively small number of partsand which can be assembled by relatively untrained personnel.

A further object of the present invention is to provide an improvedwindshield wiper arm pressure tester in which certain of the criticalparts are self-aligning and self-centering, thereby eliminating thenecessity for the use of gauges or specialized tools in assembling thetesters. @ther objects and attendant advantages of the present inventionwill readily be perceived hereafter.

The v indshield wiper arm pressure tester of the present inventionincludes a housing which is fabricated from two generally similarhalves. Each of these halves is adapted to provide the support foropposite ends of a first fulcrum pin. A main lever having spaced-apartlegs is adapted to be supported by the fulcrum pin by means of aselfaligning lit consisting, in this instance, of oversized apertures incorresponding parts of each of these legs having vertices of generallysimilar configuration to a vertex formed on the fulcrum pin. A loadreceiving platform is provided for supporting the end of a wiper arm. Asecond selfaligning fulcrum pin is located between the load bearingplatform and the main lever, the self-aligning connection between thesecond pin and the main lever being similar to that described above withrespect to the iirst fulcrum pin, with each leg of the main leversulporting one end of the second fulcrum pin. Whenever the platform issubjected to load, the main lever will pivot about the first fulcrumpin. indicating means including a pointer and a scale are associatedwith the main lever, the pointer being supported on a knife edge whichin turn has its ends supported in each half of the housing, Astabilizing lever is mounted at one end on a pin supported by oppositehalves of the housing and the other half guides the platform formovement in a predetermined path, the stabilizing lever connection tothe platform permitting the use of the above described self-aligningconnections which are rather loose. Separate adjustments are provided onthe tester for setting the zero reading of the pointer and for adjustingthe tension of a spring against which the load acts. rlhe main lever isa metal stamping and the apertures therein used for self-aligningpurposes are thus very accurately positioned during fabrication tothereby enhance the accuracy of the tester. Because one end of the iirstful-"rum pin, one end of the pin supporting the stabilizing lever, andone end of the knife edge are all supported by opposite halves of thehousing, it can reafily be seen that the internal mechanism of thetester can be placed in position in one half of the housing andthereafter the other half of the housing may be located on the firsthalf to receive the other ends of the above-mentioned elements tothereby securely hold all of the tester components in position, thisconstruction permitting the assembling of the tester by relativelyuntrained personnel. The present invention will be more fully understoodwhen the following portions of the specification are read in conjunctionwith the accompanying drawings wherein:

FIG. l is a fragmentary perspective view of an automotive vehicle withthe arm pressure tester of the present invention in position on thewindshield thereof in testing position;

FIG. 2 is a side elevation of the arm pressure tester of the presentinvention with a portion of the housing removed to disclose theorientation of the internal components;

FIG. 3 is a view taken along line IIIlH of FIG. 2;

FIG. 4 is a view taken along line lV-IV of FlG. 2;

FIG. 5 is a view taken along line V-V of FlG. 2;

FIG. 6 is a view taken along line Vl-Vl of FlG. 2;

FIG. 7 is a view taken along line Vil-Vil of FlG. 3;

FG. 8 is a detailed view of one of the plastic feet which engage thewindshield;

FlG. 9 is a view taken along line IX-IX of FIG. 3; and

FIG. l() is a view taken along line X-X of FIG. 2.

The wiper arm pressure tester of the present invention is approximately4 long, 3 high, and 1 wide. This size is convenient for permitting it totit easily in the pocket of a gas station attendant or the like and isalso of a size for convenient handling.

As can be seen from FIG. 1, the arm pressure tester lt? is adapted to bepositioned on a vehicle windshield ll for the purpose of testing thepressure of the wiper arm ll2 which is mounted proximate the windshieldin any conventional manner.

The arm pressure tester Il@ of the present invention includes a housingmade ont of two independent sections l and 14 which are preferablymolded `from a plastic material. Housing section 13 includes a locatingpin l5 which is molded integrally therewith and is adapted to lit withina mating aperture la (FIG. 5) of housing section llrl. Another locatingpin l5 in housing section i3 is `also adapted to iit in a correspondingaperture (not shown) in housing section lid. The connection lS-ld andllS with its corresponding aperture not only aid in aligning the `twohousing sections i3 and lld during assembly but also provide a certainamount of rigidity for preventing these sections from moving relative toeach other after they have been assembled. Furthermore, housing section`l?) contains a tapped protuberance ld (FIGS. 2 and 4) which is adaptedto threadably receive screw lll (FlG. 4), the head of the screw engagingthe peripheral portions of a countersunk bore in housing section llitothereby aid in holding the two housing sections together. ln addition toscrew 17 and tapped protuberance lo, additional tapped protuberances l4and i9 (FlG. 2) which are similar to protuberance le are also providedin housing section l?) and screws similar to screw Il are adapted to bepositioned in housing section )lliin a manner similar to that describedabove relative to screw ll7. Thus `in addition to the engagementprovided by pins )iS- llS and their mating apertures, there are threescrews holding the housing sections 13 and 14 together.

The mechanism for indicating the pressure of a wiper arm is `as follows:A stabilizing link Ztl has one end thereof pivotally mounted on pin 21(FlGS. 2 and 4). Pin 2l in turn has one end thereof fitting withinapertnred protuberance 22 formed integrally on housing section 13 andthe other end thereof tting Within apertured protuberance 23 formedintegrally on housing section le. rthe other end of stabilizing link Ztlis pivotally mounted by rivet (FloS. 2 and 4) on the lower end ofplatform rlhe purpose of stabilizing link 2) is for causing the platform25 to move in a substantially vertical direction when a load is appliedthereto. The housing lil is upright and has a basal extension in whichthe platform is arranged for easy access. The operating mechanism isthus contained within a chamber of L-shape. By grasping the uprightportion by the hand the platform is readily placed beneath a wiper arm.

Platform 25 has a self-aligning load bearing pin or fulcrum 26 rigidlysecured therein by set screw 27 (FlGS. 2 and 3). Fulcrum 26 is ofsubstantially square cross section and the aperture in platfonm 25 inwlL'ch is located is of like cross section. The outer ends of loadbearing pin 26 lit loosely in sector-like shaped apertures 2S (FIG. 7)located toward the end `of main lever 29. As can be seen from FIG. 3,main lever 29 includes two legs 3@ and 3i which straddle the centralportion of platform 25 and these legs are connected at a point proximatethe platform by la rivet 32, the spacing between legs 3d `and 3l beingdetermined by space-r 33. The extreme outer end portions of legs Sil andTal of main lever 29 have sect-or shaped apertures therein for receivingself-aligning fulcrum pin 35, the ends of which are anchored inprotuberances 3o and 37 in housing portions 13 and ld, respectively, theprotuberances being integrally molded parts of the housing portions.Fulcrum pin 35 is of generally square cross sect-ion and tits in matingsquare apertures in protuberances 36 and 37, the latter holding pin 35in the orientation shown in the drawings. lt can readily be seen tromFlG. 7 that the lower portion of sector shaped opening 23 is of aJ-shape and the upper .part of sector shaped opening 34 is also of aV-shape. Thus when a load is applied to platform 25, one corner `orknife edge of pins 2.5 and 35 will engage the V-shaped portions ofsectors 28 and 34, respectively, and in this manner the length of themain lever between the yffulcrum pin 35 and load bearing pin or fulcrum26 is accurately predetermined. The value of the `foregoing arrangementis in the fact that the sector-like apertures in legs 3@ and 3l arelocated by a die punching operation, and the fact that pins 26 and 35are self-locating on main lever 29 to permit accurate pressuremeasurements by the use of a mass produced part.

The ends of legs 3d and 3l of main lever 29 which are remote from pin 35straddle a plastic block 38 and are secured thereto by rivets 39 andliti. The outer end il of block 38 has a radius of curvature the centerof which is ulcrum pin 35. One end of band or ribbon 42 is secured toblock 38 by rivet i3 and the other end of band 42 is secured to `springlid. The intermediate portion of band 42 is staked to cam 45 by rivet46. The end of spring ld remote from its connection with band 4t2 ishooked onto plate i7 (FlGS. 2 and 10). Secured to cam 45 by means ofrivet dii is a dual pointer 49 having hands 5@ and 5l Iformed from asingle stamping and connected to each other by integral rib 52. Cam l5has a slot therein which receives blade 53. As can be seen from FlG. 6,a set screw 54 is adapted to engage a cut-away section 55 of blade 53 tothereby hold it in rm engagement in the slot (not numbered) in cam 45.Each end of blade 53 is adapted to lit in a `cut-away portion of eachhousing l and ld (HG. 9). Each cut-away portion is of a conguration toreceive a steel insert 56, the knife edge 57 resting at the vertex 5Sformed therein.

'It can readily be seen therefore that when a load is applied toplatform 25, the latter will move downwardly, as guided by itsconnection with the housing through stabilizing link 2li. Becauseplatform 25 can pivot about the axis of rivet 24, load bearing pin 26will be able to seat itself in sector shaped cutout 28 with the cornerof square pin 2e resting in the vertex of the cutout. Like- Cil wise,main lever 29 will be able to adjust itself so that the iulcrum pin 35mounted in the housing will support it at the vertex of sector shapedcutout ln essence therefore a third-class lever is provided wherein thetraveloi the outer end of plastic block will be magnified when comparedto the movement of platform 25. The downward movement of block 3S willbe against the bias oi spring A and the movement oi cam i5 to which band42 is attached will result in the movement of pointer 49 to give anindication on the scale or chart Scale or chart 59, which is printed inounces of pressure on both sides thereof, is secured to housing sectionl by plastic pips 6i? extending from protuberances @l (FG. 5) moldedintegrally with housing section l, the plastic pips iitting I Ilapertures in the scale and being deformed after the scale is positionedthereon. Thus the scale is held between the shoulders on protuberances(il and the deformed pips. Each housing section lil and ld has a clearplastic window such as e?. therein, the latter fitting in a moldeddepression in the housing and being secured thereto by i'using of theplastic. Housing section i3 has an apertured protuberance e3 forpermitting the scale to be hung on a hook, if this is desired.

There are two independent adiustments in the wiper arm tester. rthefirst is for adjusting the pointer at the zero mark. adjust-mentconsists ci' a screw dfi (RGS. 2 and 4) the lower of which is adapted tobe received in an aperture in protuberance iorfned in-v tegrally inhousing section rihreadabiy mounted on screw 6d is a plate 6o and thelatter is biased downwardly by spring e7 interposed between it and asection of the housing. This positioning of spring 67 retains screw 6:4in `the housing. As can be seen from HG. 3, one end of plate 66 lislocated close to the wall of housing i3, and this iit prevents plate 66from turning when screw 66 is turned. Plate 6e is adapted to bear on thetop o hloclf when there is no load on pla form 25 and thus theadjustment of screw is utilized to set pointer i9 at zero to provide theinitial scale reading.

The other adiustment is for setting the tension in the spring. To thisend a screw 68 (FiGS. 2 and 1G) has the head 69 thereo gournaled Jforrotation in the' lower portion of U-shaped portion 'itl formedintegrally with the side of housing l?. The upper end of U-shapedportion is provided with an aperture for receiving the end of screwremote from head 69. A spring 'i2 encircles screw ed and the lower end othe spring bears on the inner side of the tti-shaped portion and theupper end bears on the underside of plate i7 which is tapped to receivescrew `(t3. ln this manner, spring '72 retains screw 6b in the housing.lt can readily bc seen therefore that as screw ed is turned, plate (i7will move up or down and thus cause the end or" spring d4 attachedthereto to move up or down, accordingly. After the spring has been adJjusted at the factory, plastic plug is inserted in the housing to coverthe screw head lt can readily be seen that the zero adjustment isindependent of the spring tension adjustment and that the adjustment ofthe former will not aLect the accuracy of the latter.

portion d5, about which band lits, is of such a conhguration so that theeccentric portion to the left of blade 53 (PEG. 2) counterbalances theweight or pointer i9 thereby preventing any inaccuracy in the scalereading due to the weight of the pointer. rEhe cam, by effectivelycausing vthe downward force exerted by main lever on cam to act througha shorter lever `arm than the arm through which spring 14E-4i actsermits the latter to be of a relatively weak construction.

As can be seen from 3, 6, and 9, thc outer lateral extremities 53 ofknife edge 53 are in the form of a point. ln other words the ends 53 ofthe knife edge converge inwardly from the bottom. Therefore, when knifeedge 53 is in position on inserts 56, the only Contact between the knifeedge and side walls 5o of inserts 5e is at points 53', this :arrangementpreventing the entire ends 53" of the knife edge from frictionallyengaging the walls 55 thereby obv-iating any inaccuracy due to frictiontherebetween. Furthermore, the length of knife edge 53 is less than thedistance between walls 5e. Therefore both extremities 53 cannot be inengagement with both walls at the same time. The side walls associatedwith inserts Se are preferably separate metal discs formed by a simplestamping operation.

The knife edge il?)` is self-aligning and self-centering within cam 45.More specifically, as noted above, the upper portion of knife edge 53fits within a slot in cam d5. Furthermore, set screw lits into a centralslot in knife edge 5?. Since the slot in the cam l5 and the dimensionsof knife edge S3 are held to certain tolerances, once set screw 5d istightened in position the lower edge of knife edge 53 is positioned atthe desired location within cam Furthermore, the outer points 53 arepositively located in an automatic manner as a result of tightening setscrew 5tlin the central slot in the knife edge. Thus knife edge 53,which serves as a pivot for cam l5 and the pointer d@ Imounted thereon,is self-aligning and selfcentering incidental to its installation in camd5, thereby permitting this knife edge to lbe installed by relativelyuntrained personnel.

is can be seen from FlGS. 2, 5, and 8, rubber pads 73 are adapted to beinserted in the housing. Three pads are used so as to provide threepoints at which the underside of the arm pressure tester rests on thewindshield. ln this manner firm Contact with the windshield is assured.Pad 73 consists of a base portion 74- and a tapered portion connected byan intermediate neck portion 76. in assembly tapered portion 75 isinserted through a hole in the housing and the enlarged part of taperedportion retains the pad 1in the housing.

lt can readily be seen that the small travel of platform 2S, due to thelinkage which is used for magnifying the travel of the platform, permitsthe pressure of the spring in the wiper arm to be read at the positionwhich it normally occupies when a wiper blade is mounted on the endthereof.

'ln accordance with the present invention the lower surface of blockFIG. 2) is adapted to engage the upper surfaces of protuberances and 23(FTG. 4) when block has traveled its maximum downward distance. ln otherwords, protuberances 22 and 23 act as a positive stop for mai' lever Z9.

The pressure tester of the present invention `can readily be assembledby relatively untrained personnel. Plates and i7 are inserted. in thehousing and secured to the screws lwith which they are associated in amanner which is obvious from mere inspection. Disks Se are dropped intothe housing halves and bearings or inserts 56 are located and pressedinto the housing halves by the use of a xture, the bearings holdingdisks 56 in place. The windows 62 are then heat sealed into the housinghalves, as described above. Thereafter a subassembly is made up from cam#'55, main lever Z9, platform 25, and stabilizing link Ztl. Morespecifically, pointer Il@ is slid over cam di? and knife edge 53 ispositioned in aligned slots in the pointer and the cam. Thereafter setscrew 5d is inserted in cam and the end of the set `screw is located inthe slot in the knife edge 53, thereby providing the abovedescribedself-centering and self-locating action. Rivet is then inserted tosecure pointer J2 to cam d5. Plastic block is riveted to thespaced-apart legs Si) and 3l of the main lever. Thereafter spacer 33`and rivet 32 are assembled in the main lever. Stabilizing link Ztl isriveted to platform by rivet 2.4. Platform 2S is positioned between thespaced-apart legs 3@ and 3l of main lever 29 and fulcrurn 2o is placedin position in the platform with the ends of the fulcrum in position inthe self-centering openings of the main lever. Set screw 27 is thentightened to secure fulcuunr 26 in the platform Band Il?. is then stakedto both plastic block 3S and cam 45, thereby completing a subassembly ofthe cam 411-5, band 4Z, main lever d 29, and stabilizing link 2d. Pin 2and ful'crurn 35 arel then located in housing half 13. Thereafter thesubassembly consisting of the stabilizing link 2d, main lever 29,platform 25, and cam are inserted in housing half 13 with thestabilizing link 20 fitting on pin 21 and the apertures .lift in mainlever 29 receiving pin 35, and with one end 53 of knife edge S3positioned on metallic insert Se. Spring d4 is then connected betweenband d2 and plate 47. Scale or chart S9 is then pl-aced in position inhousing half 13 in the manner described above. To complete the assembly,housing half M is placed in position on housing half 13, housing halfld. receiving the other end of fulcrum 35, the other end of knife edge53, the other end of stabilizing pin 2l, and protuberances or locatingpins l5 and l5 from housing half T13. Thereafter it is only necessary toinsert the three screws, such -as l?, in tapped apertures lo, l, and wand tighten them to secure the housing halves in position with all theinternal components of the tester located therein in the requiredmanner. Furthermore, a tapped aperture i9 may be supplied in housinghalf 1? to receive a fourth screw like l' to securely hold the housinghalves together in the area of scale or chart 59. ln lieu of the abovedescribed deforming of plastic pips ed to hold the scale in position,protuberances (not shown) may be formed integrally with housing half ldin opposition to protuberances le in housing half i3, the opposedprotuberances cooperating to engage opposite sides of the scale or chart59 in a vise like grip when the screw is tightened in tapped aperturei9. Thereafter the zero adjustment and the spring tension adjustmentscrews are manipulated to calibrate the device. lt can thus be seen thatin View of the above described construction of the various components ofthe instant tester, and in View of the method in which it is assembled,the assembly can be effected by relatively untrained personnel having aminimum of instruction. Furthermore, since the accuracy of the scale isdependent on its inherent construction rather than on the skill withwhich the components are assembled, the tester will provide accuratereadings notwithstanding that relatively untrained personnel can beutilized in its assembly.

vhile a preferred embodiment of the present invention is disclosed, itis to be understood that it is not limited thereto, but may be otherwiseembodied within the scope of the following claims.

What is claimed is:

`l. A portable wiper arm pressure tester comprising a housing having anupright body with a lbasal extension and forming therewith an L-shapedchamber opening upwardly from the extension, the upright body portion ofthe housing being formed to be grasped as a handle to facili-tate theplacement of the basal extension and its platform beneath the outer endof a wiper arm on a windshield, a platform having a stem portiondepending through the chamber opening, a main lever having fulcrumsupport in opposed wall bearings within the extension, means providingfulcrum support for the stem portion on the lever to guide the platformin its testing movement in the eX- tcnsion opening, pointer means,iournalcd upon a transverse axis within the upright chamber portion inthe handle, the free end of the main lever extending from the basalextension into the upright chamber portion at a point beneath thetransverse axis, a flexible connecting member extending upwardly fromthe .free end to the pointer means, said pointer means carrying aneccentric cam member of greater radial extent from the transverse axisthan the flexible member to provide a relatively longer arm, and springmeans connected to the cam member and acting therethrough to actuate thepointer means.

2. A portable pressure tester for a `windshield wiper arm or the likecomprising a housing fabricated from two generally similar halves, afulcrfum pin having its ends supported Iby each of said housing halves,a main lever having spaced-apart legs, corresponding portions of each ofsaid legs being mounted on said fulcruim pin by means of a self-aligningt, a platform supported by and between said legs, a second fulcrum pincou-pled between said platform and corresponding portions on each ofsaid legs by means of a selfaligniiig fit, and indicating meansoperatively coupled to said main lever, said indicating means includinga pointer associated with a scale mounted in said housing half, knifeedge means for supporting said pointer with the opposite ends of saidknife edge supported in each half of said housing, guide means tying theplatform to one housing half, said iirst fulcrum pin and said knife edgemeans each having one end supported in the other housing half, and meansfor securing the two housing halves together to operati 7ely enclose thetesting mechanism aforesaid whereby the placing orr a load on saidplatform results in a detdection of said indicating means of an amountwhich proportional to the magnitude or" said load.

3. A pressure tester for a windshield wiper arm or the like comprising ahousing, a platform niovably mounted in said housing, a stabilizing linkfor guiding said platform in a predetermined direction, a main levermounted in said housing for movement about a fulcruin pin, a loadbearing pin couplin" said platform and said main lever for relativepivotal movement during link-guided motion of the platform, pointermeans carried by a cani, said cani eing mounted for pivotal movementabout a hired axis and eccentric thereto, flexible band `means coupledat one end to the free end of said main iever, at its other end tospring means and intermediate its ends to said eccentric cam, saidspring means acting in opposition to a load `applied to said platform.,whereby said main lever is operative to move the pointer through oneleverage and said spring is operative to move the pointer through adiierent leverage.

Refer-enses Cited in the of this patent

1. A PORTABLE WIPER ARM PRESSURE TESTER COMPRISING A HOUSING HAVING ANUPRIGHT BODY WITH A BASAL EXTENSION AND FORMING THEREWITH AN L-SHAPEDCHAMBER OPENING UPWARDLY FROM THE EXTENSION, THE UPRIGHT BODY PORTION OFTHE HOUSING BEING FORMED TO BE GRASPED AS A HANDLE TO FACILITATE THEPLACEMENT OF THE BASAL EXTENSION AND ITS PLATFORM BENEATH THE OUTER ENDOF A WIPER ARM ON A WINDSHIELD, A PLATFORM HAVING A STEM PORTIONDEPENDING THROUGH THE CHAMBER OPENING, A MAIN LEVER HAVING FULCRUMSUPPORT IN OPPOSED WALL BEARINGS WITHIN THE EXTENSION, MEANS PROVIDINGFULCRUM SUPPORT FOR THE STEM PORTION ON THE LEVER TO GUIDE THE PLATFORMIN ITS TESTING MOVEMENT IN THE EXTENSION OPENING, POINTER MEANSJOURNALED UPON A TRANSVERSE AXIS WITHIN THE UPRIGHT CHAMBER PORTION INTHE HANDLE, THE FREE END OF THE MAIN LEVER EXTENDING FROM THE BASALEXTENSION INTO THE UPRIGHT CHAMBER PORTION AT A POINT BENEATH THETRANSVERSE AXIS, A FLEXIBLE CONNECTING MEMBER